What are the Big Ideas that will change the world? Friends of the Earth is inviting answers as part of its new project which launched online yesterday (24 June) with a series of provocations, starting with the future of the city.
Drawing on human ingenuity, creativity and expertise, Friends of the Earth asks what are the practical solutions and interventions needed to shape a better city for the future - and how can tomorrow's cities help deliver quality of life and wellbeing for future city dwellers.
More than half of the world population already live in cities, but what will the urban spaces of the future look like? What do we need to do to make them future-proof, to provide the quality of life we want and to meet the environmental challenges we face.
Will city dwellers learn to share and share alike? London's former Mayor, Ken Livingstone tells Friends of the Earth how sharing things - from power tools to books and ideas - can help make our cities more sustainable.
Different cities face their own unique challenges and the project explore the benefits of cities going it alone, developing their own economies, introducing city-wide taxation, developing their own infrastructure, or legal and political systems. It asks whether grassroots democracy might hold the key to city living.
City author Leo Hollis tells Friends of the Earth why he think cities are good for you - while Friends of the Earth campaigner Jane Thomas explains what it is that makes the city she lives in great.
Mike Childs, project leader for Big Ideas Change the World, said: "We know we need to make changes to the way we live on our planet if we're going to dig ourselves out of the mighty big hole we're currently in.
"Big Ideas Change the World is all about identifying how we can do that. We're an incredible species, and by working together, we think we can find a way forward.
"Where better to start than with cities - the places where most of the human population now lives."